Synthesis and in vitro evaluation of 18F‐β‐carboline alkaloids as PET ligands |
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Authors: | Elisabeth Blom Farhad Karimi Olof Eriksson Håkan Hall Bengt Långström |
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Affiliation: | 1. Department of Biochemistry and Organic Chemistry, Uppsala University, Box 576, Husargatan 3, BMC, S‐751 23 Uppsala, Sweden;2. Department of Radiology, Oncology and Clinical Immunology, Division of Radiology, Rudbeck Laboratory, Uppsala University, S‐751 85 Uppsala, Sweden;3. Uppsala Applied Science Lab, GEHC, Box 967, S‐751 09 Uppsala, Sweden;4. Uppsala Imanet, GEHC, Box 967, S‐751 09 Uppsala, Sweden |
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Abstract: | A one‐step 18F‐labelling strategy was used to prepare four 18F‐labelled analogues of 7‐methoxy‐1‐methyl‐9H‐β‐carboline (harmine): 7‐(2‐[18F]fluoroethoxy)‐1‐methyl‐9H‐β‐carboline (5), 7‐(3‐[18F]fluoro‐propoxy)‐1‐methyl‐9H‐β‐carboline (6), 7‐[2‐(2‐[18F]fluoroethoxy)ethoxy]‐1‐methyl‐9H‐β‐carboline (7), and 7‐{2‐[2‐(2‐[18F]fluoroethoxy)ethoxy]‐ethoxy}‐1‐methyl‐9H‐β‐carboline (8). These were synthesized as potential positron emission tomography ligands for monoamine oxidase A (MAO‐A). A solution of pure labelled compound in buffer was obtained in <70 min from end of radionuclide production, with a decay‐corrected yield of up to 23%. The average specific binding to MAO‐A in rat brain, determined by autoradiography experiments, was highest for compounds 7 and 8 (89±2 and 96±1%, respectively), which was obtained at <1 nM radioligand concentration. Copyright © 2008 John Wiley & Sons, Ltd. |
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Keywords: | harmine analogues nucleophilic 18F‐fluorination one‐step labelling β ‐carboline alkaloids MAO‐A |
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